Concorde
Concorde (/ˈkɒŋkɔːrd/) is a retired Anglo-French supersonic airliner jointly developed and manufactured by Sud Aviation (later Aérospatiale) and the British Aircraft Corporation (BAC). Studies started in 1954, and France and the UK signed a treaty establishing the development project on 29 November 1962, as the programme cost was estimated at £70 million (£1.39 billion in 2021). Construction of the six prototypes began in February 1965, and the first flight took off from Toulouse on 2 March 1969. The market was predicted for 350 aircraft, and the manufacturers received up to 100 option orders from many major airlines. On 9 October 1975, it received its French Certificate of Airworthiness, and from the UK CAA on 5 December.[4]
For other uses, see Concorde (disambiguation).
Concorde is a tailless aircraft design with a narrow fuselage permitting 4-abreast seating for 92 to 128 passengers, an ogival delta wing and a droop nose for landing visibility.
It is powered by four Rolls-Royce/Snecma Olympus 593 turbojets with variable engine intake ramps, and reheat for take-off and acceleration to supersonic speed.
Constructed out of aluminium, it was the first airliner to have analogue fly-by-wire flight controls.
The airliner could maintain a supercruise up to Mach 2.04 (2,170 km/h; 1,350 mph) at an altitude of 60,000 ft (18.3 km).
Delays and cost overruns increased the programme cost to £1.5–2.1 billion in 1976, (£9–13.2 billion in 2021).
Concorde entered service on 21 January of that year with Air France from Paris-Roissy and British Airways from London Heathrow.
Transatlantic flights were the main market, to Washington Dulles from 24 May, and to New York JFK from 17 October 1977.
Air France and British Airways remained the sole customers with seven airframes each, for a total production of twenty.
Supersonic flight more than halved travel times, but sonic booms over the ground limited it to transoceanic flights only.
Its only competitor was the Tupolev Tu-144, carrying passengers from November 1977 until a May 1978 crash, while a potential competitor, the Boeing 2707, was cancelled in 1971 before any prototypes were built.
On 25 July 2000, Air France Flight 4590 crashed shortly after take-off with all 109 occupants and four on the ground killed. This was the only fatal incident involving Concorde; commercial service was suspended until November 2001.
The Concorde aircraft were retired in 2003, 27 years after commercial operations had begun. All but 2 of the 20 aircraft built have been preserved and are on display across Europe and North America.
Development[edit]
Early studies[edit]
The origins of the Concorde project date to the early 1950s, when Arnold Hall, director of the Royal Aircraft Establishment (RAE), asked Morien Morgan to form a committee to study the supersonic transport (SST) concept. The group met for the first time in February 1954 and delivered their first report in April 1955.[5] At the time it was known that the drag at supersonic speeds was strongly related to the span of the wing.[N 1] This led to the use of short-span, thin trapezoidal wings such as those seen on the control surfaces of many missiles, or in aircraft such as the Lockheed F-104 Starfighter interceptor or the planned Avro 730 strategic bomber that the team studied. The team outlined a baseline configuration that resembled an enlarged Avro 730.[6]
This same short span produced very little lift at low speed, which resulted in extremely long take-off runs and high landing speeds.[7] In an SST design, this would have required enormous engine power to lift off from existing runways and, to provide the fuel needed, "some horribly large aeroplanes" resulted.[6] Based on this, the group considered the concept of an SST infeasible, and instead suggested continued low-level studies into supersonic aerodynamics.[6]
Slender deltas[edit]
Soon after, Johanna Weber and Dietrich Küchemann at the RAE published a series of reports on a new wing planform, known in the UK as the "slender delta" concept.[8][9] The team, including Eric Maskell whose report "Flow Separation in Three Dimensions" contributed to an understanding of the physical nature of separated flow,[10] worked with the fact that delta wings can produce strong vortices on their upper surfaces at high angles of attack.[6] The vortex will lower the air pressure and cause lift to be greatly increased. This effect had been noticed earlier, notably by Chuck Yeager in the Convair XF-92, but its qualities had not been fully appreciated. Weber suggested that this was no mere curiosity, and the effect could be used deliberately to improve low speed performance.[9][6]
Küchemann's and Weber's papers changed the entire nature of supersonic design almost overnight. Although the delta had already been used on aircraft prior to this point, these designs used planforms that were not much different from a swept wing of the same span.[N 2] Weber noted that the lift from the vortex was increased by the length of the wing it had to operate over, which suggested that the effect would be maximised by extending the wing along the fuselage as far as possible. Such a layout would still have good supersonic performance inherent to the short span, while also offering reasonable take-off and landing speeds using vortex generation.[9] The only downside to such a design is that the aircraft would have to take off and land very "nose high" to generate the required vortex lift, which led to questions about the low speed handling qualities of such a design.[11] It would also need to have long landing gear to produce the required angle of attack while still on the runway.
Küchemann presented the idea at a meeting where Morgan was also present. Test pilot Eric Brown recalls Morgan's reaction to the presentation, saying that he immediately seized on it as the solution to the SST problem. Brown considers this moment as being the true birth of the Concorde project.[11]
Impact[edit]
Environmental[edit]
Before Concorde's flight trials, developments in the civil aviation industry were largely accepted by governments and their respective electorates. Opposition to Concorde's noise, particularly on the east coast of the United States,[302][303] forged a new political agenda on both sides of the Atlantic, with scientists and technology experts across a multitude of industries beginning to take the environmental and social impact more seriously.[304][305] Although Concorde led directly to the introduction of a general noise abatement programme for aircraft flying out of John F. Kennedy Airport, many found that Concorde was quieter than expected,[70] partly due to the pilots temporarily throttling back their engines to reduce noise during overflight of residential areas.[306] Even before commercial flights started, it had been claimed that Concorde was quieter than many other aircraft.[307] In 1971, BAC's technical director was quoted as saying, "It is certain on present evidence and calculations that in the airport context, production Concordes will be no worse than aircraft now in service and will in fact be better than many of them."[308]
Concorde produced nitrogen oxides in its exhaust, which, despite complicated interactions with other ozone-depleting chemicals, are understood to result in degradation to the ozone layer at the stratospheric altitudes it cruised.[309] It has been pointed out that other, lower-flying, airliners produce ozone during their flights in the troposphere, but vertical transit of gases between the layers is restricted. The small fleet meant overall ozone-layer degradation caused by Concorde was negligible.[309] In 1995, David Fahey, of the National Oceanic and Atmospheric Administration in the United States, warned that a fleet of 500 supersonic aircraft with exhausts similar to Concorde might produce a 2 per cent drop in global ozone levels, much higher than previously thought. Each 1 per cent drop in ozone is estimated to increase the incidence of non-melanoma skin cancer worldwide by 2 per cent. Dr Fahey said if these particles are produced by highly oxidised sulphur in the fuel, as he believed, then removing sulphur in the fuel will reduce the ozone-destroying impact of supersonic transport.[310]
Concorde's technical leap forward boosted the public's understanding of conflicts between technology and the environment as well as awareness of the complex decision analysis processes that surround such conflicts.[311] In France, the use of acoustic fencing alongside TGV tracks might not have been achieved without the 1970s controversy over aircraft noise.[312] In the UK, the CPRE has issued tranquillity maps since 1990.[313]